The helicopter that crashed, killing basketball great Kobe Bryant, his daughter and seven others, was not certified to fly in foggy conditions.
According to officials, Island Express Helicopters, which owned the Sikorsky S-76B that crashed, was allowed to operate under visual flight rules.
"The preliminary information is Island Express' 135 certificate did not allow for IFR flight," said Keith Holloway, a National Transportation Safety Board spokesman. "No other specifics are available at this time."
Preliminary investigations have pegged foggy weather conditions as a possible cause for the crash.
Meanwhile, the Lakers played their first game since Bryant's death, and paid tribute to the star by wearing his numbers - 8 and 24 - during warm-up. They went against the Portland Trail Blazers at the Staples Center in LA.


Israel reopens Gaza's Rafah border crossing to Egypt, with limits
Russian drone strike kills 12 miners in Ukraine
Five-year-old boy returns to Minnesota after ICE release
Reopening of Gaza's Rafah crossing expected Monday
Winter storm death toll in United States reaches 90
Pakistan says 145 militants killed after attacks in Balochistan
Israeli strikes kill 26 in Gaza, health officials say
US government starts likely brief shutdown as House fails to approve deal
